1. Field of the Invention
This invention relates to a mobile machine, in particular a counterweighted fork lift truck, with at least one pressurized tank for carrying fuel which is in a gaseous state under normal conditions. The invention also relates to a pressurized tank for an industrial truck.
2. Technical Considerations
Mobile machines are frequently operated with fuels that are in a gaseous state under normal (e.g., ambient) conditions. In addition to hydrocarbon-based fuels, such as propane, butane and methane, increasing use is being made of hydrogen, which can be used to operate a fuel cell unit, for example. The mobile machine generally has one or more pressurized tanks for the storage of these fuels. To be able to store the largest possible quantity of fuel, the tanks are generally pressurized at relatively high pressures, conventionally more than 25 bar and typically on the order of magnitude of 200 bar, as high as 350 bar for hydrogen, and, in individual cases, as high as 700 bar.
In mobile applications, an objective is generally to make the components as lightweight as possible to increase the cargo-carrying capacity of the vehicle. With fuel tanks of the known art, attempts have consequently been made to design the fuel tanks so that they are as lightweight and simultaneously as stable as possible, for which reason aluminum alloys or compound materials are used. An additional objective of tanks of the known art is to achieve maximum filling pressures and, therefore, maximum filling quantities while using the minimum quantities of material. As a result of which, the tanks are generally cylindrical or spherical in shape with an approximately uniform wall thickness. However, tanks of this type utilize the available space inefficiently, especially if two or more such tanks are located next to each other because unused space remains between the tanks or between the tanks and a housing wall, which is generally flat and straight. Locating the tank(s) at a location outside the chassis of the vehicle, as is frequently done on vehicles that are operated with liquefied natural gas, avoids this problem but has the disadvantage that the tank is exposed without protection to environmental factors, including but not limited to mechanical damage and solar radiation. Additionally, outboard installation restricts accessibility to the vehicle and/or the view of the vehicle operator. The installation of additional components in the vicinity of tanks of the known art is also made more difficult on account of the round geometry, and frequently requires complex and expensive supplemental brackets and mountings which are attached to the surrounding frame or housing components.
An object of the invention is, therefore, to create a mobile machine, in particular a counterweighted fork lift truck, with at least one pressurized tank, in particular to carry fuel that is in a gaseous state under normal (i.e., ambient) conditions, which has a high level of operational safety and reliability and a long period of operation, has a simple construction, makes optimal utilization of space, and makes possible particularly economical operation.
An additional object of the invention is to create a pressurized tank for a mobile machine that has a high level of operational safety and a long period of operation, has a simple construction, and makes possible particularly economical operation.